In the field of superconducting magnets it is known to employ a cooling technology with little or even no cryogenic liquid such as liquid helium. Superconducting magnets of this type are often referred to as “cryogen-free magnets” and have the obvious advantage of hardly containing or consuming helium. Due to the absence of a reservoir of cryogenic liquid, however, the thermal buffering capability of cryogen-free magnet is limited. The U.S. Pat. No. 5,410,286 discloses a cryocooler-cooled superconducting magnet with a thermal buffer assembly in contact with the magnet cartridge that includes the superconducting wire. This known thermal buffer assembly is coupled via a passing gas charge/discharge system to a He-source and to ambient air.